// Copyright (c) 2014-2016 The Bitcoin Core developers
// Copyright (c) 2017-2019 The Raven Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "chain.h"
#include "util.h"
#include "test/test_raven.h"

#include <vector>

#include <boost/test/unit_test.hpp>

#define SKIPLIST_LENGTH 300000

BOOST_FIXTURE_TEST_SUITE(skiplist_tests, BasicTestingSetup)

    BOOST_AUTO_TEST_CASE(skiplist_test)
    {
        BOOST_TEST_MESSAGE("Running SkipList Test");

        std::vector<CBlockIndex> vIndex(SKIPLIST_LENGTH);

        for (int i = 0; i < SKIPLIST_LENGTH; i++)
        {
            vIndex[i].nHeight = i;
            vIndex[i].pprev = (i == 0) ? nullptr : &vIndex[i - 1];
            vIndex[i].BuildSkip();
        }

        for (int i = 0; i < SKIPLIST_LENGTH; i++)
        {
            if (i > 0)
            {
                BOOST_CHECK(vIndex[i].pskip == &vIndex[vIndex[i].pskip->nHeight]);
                BOOST_CHECK(vIndex[i].pskip->nHeight < i);
            } else
            {
                BOOST_CHECK(vIndex[i].pskip == nullptr);
            }
        }

        for (int i = 0; i < 1000; i++)
        {
            int from = InsecureRandRange(SKIPLIST_LENGTH - 1);
            int to = InsecureRandRange(from + 1);

            BOOST_CHECK(vIndex[SKIPLIST_LENGTH - 1].GetAncestor(from) == &vIndex[from]);
            BOOST_CHECK(vIndex[from].GetAncestor(to) == &vIndex[to]);
            BOOST_CHECK(vIndex[from].GetAncestor(0) == vIndex.data());
        }
    }

    BOOST_AUTO_TEST_CASE(getlocator_test)
    {
        BOOST_TEST_MESSAGE("Running GetLocator Test");

        // Build a main chain 100000 blocks long.
        std::vector<uint256> vHashMain(100000);
        std::vector<CBlockIndex> vBlocksMain(100000);
        for (unsigned int i = 0; i < vBlocksMain.size(); i++)
        {
            vHashMain[i] = ArithToUint256(i); // Set the hash equal to the height, so we can quickly check the distances.
            vBlocksMain[i].nHeight = i;
            vBlocksMain[i].pprev = i ? &vBlocksMain[i - 1] : nullptr;
            vBlocksMain[i].phashBlock = &vHashMain[i];
            vBlocksMain[i].BuildSkip();
            BOOST_CHECK_EQUAL((int) UintToArith256(vBlocksMain[i].GetBlockHash()).GetLow64(), vBlocksMain[i].nHeight);
            BOOST_CHECK(vBlocksMain[i].pprev == nullptr || vBlocksMain[i].nHeight == vBlocksMain[i].pprev->nHeight + 1);
        }

        // Build a branch that splits off at block 49999, 50000 blocks long.
        std::vector<uint256> vHashSide(50000);
        std::vector<CBlockIndex> vBlocksSide(50000);
        for (unsigned int i = 0; i < vBlocksSide.size(); i++)
        {
            vHashSide[i] = ArithToUint256(i + 50000 + (arith_uint256(1)
                    << 128)); // Add 1<<128 to the hashes, so GetLow64() still returns the height.
            vBlocksSide[i].nHeight = i + 50000;
            vBlocksSide[i].pprev = i ? &vBlocksSide[i - 1] : (vBlocksMain.data() + 49999);
            vBlocksSide[i].phashBlock = &vHashSide[i];
            vBlocksSide[i].BuildSkip();
            BOOST_CHECK_EQUAL((int) UintToArith256(vBlocksSide[i].GetBlockHash()).GetLow64(), vBlocksSide[i].nHeight);
            BOOST_CHECK(vBlocksSide[i].pprev == nullptr || vBlocksSide[i].nHeight == vBlocksSide[i].pprev->nHeight + 1);
        }

        // Build a CChain for the main branch.
        CChain chain;
        chain.SetTip(&vBlocksMain.back());

        // Test 100 random starting points for locators.
        for (int n = 0; n < 100; n++)
        {
            int r = InsecureRandRange(150000);
            CBlockIndex *tip = (r < 100000) ? &vBlocksMain[r] : &vBlocksSide[r - 100000];
            CBlockLocator locator = chain.GetLocator(tip);

            // The first result must be the block itself, the last one must be genesis.
            BOOST_CHECK(locator.vHave.front() == tip->GetBlockHash());
            BOOST_CHECK(locator.vHave.back() == vBlocksMain[0].GetBlockHash());

            // Entries 1 through 11 (inclusive) go back one step each.
            for (unsigned int i = 1; i < 12 && i < locator.vHave.size() - 1; i++)
            {
                BOOST_CHECK_EQUAL(UintToArith256(locator.vHave[i]).GetLow64(), tip->nHeight - i);
            }

            // The further ones (excluding the last one) go back with exponential steps.
            unsigned int dist = 2;
            for (unsigned int i = 12; i < locator.vHave.size() - 1; i++)
            {
                BOOST_CHECK_EQUAL(UintToArith256(locator.vHave[i - 1]).GetLow64() - UintToArith256(locator.vHave[i]).GetLow64(), dist);
                dist *= 2;
            }
        }
    }

    BOOST_AUTO_TEST_CASE(findearliestatleast_test)
    {
        BOOST_TEST_MESSAGE("Running Findearliestatleast Test");

        std::vector<uint256> vHashMain(100000);
        std::vector<CBlockIndex> vBlocksMain(100000);
        for (unsigned int i = 0; i < vBlocksMain.size(); i++)
        {
            vHashMain[i] = ArithToUint256(i); // Set the hash equal to the height
            vBlocksMain[i].nHeight = i;
            vBlocksMain[i].pprev = i ? &vBlocksMain[i - 1] : nullptr;
            vBlocksMain[i].phashBlock = &vHashMain[i];
            vBlocksMain[i].BuildSkip();
            if (i < 10)
            {
                vBlocksMain[i].nTime = i;
                vBlocksMain[i].nTimeMax = i;
            } else
            {
                // randomly choose something in the range [MTP, MTP*2]
                int64_t medianTimePast = vBlocksMain[i].GetMedianTimePast();
                int r = InsecureRandRange(medianTimePast);
                vBlocksMain[i].nTime = r + medianTimePast;
                vBlocksMain[i].nTimeMax = std::max(vBlocksMain[i].nTime, vBlocksMain[i - 1].nTimeMax);
            }
        }
        // Check that we set nTimeMax up correctly.
        unsigned int curTimeMax = 0;
        for (unsigned int i = 0; i < vBlocksMain.size(); ++i)
        {
            curTimeMax = std::max(curTimeMax, vBlocksMain[i].nTime);
            BOOST_CHECK(curTimeMax == vBlocksMain[i].nTimeMax);
        }

        // Build a CChain for the main branch.
        CChain chain;
        chain.SetTip(&vBlocksMain.back());

        // Verify that FindEarliestAtLeast is correct.
        for (unsigned int i = 0; i < 10000; ++i)
        {
            // Pick a random element in vBlocksMain.
            int r = InsecureRandRange(vBlocksMain.size());
            int64_t test_time = vBlocksMain[r].nTime;
            CBlockIndex *ret = chain.FindEarliestAtLeast(test_time);
            BOOST_CHECK(ret->nTimeMax >= test_time);
            BOOST_CHECK((ret->pprev == nullptr) || ret->pprev->nTimeMax < test_time);
            BOOST_CHECK(vBlocksMain[r].GetAncestor(ret->nHeight) == ret);
        }
    }

    BOOST_AUTO_TEST_CASE(findearliestatleast_edge_test)
    {
        BOOST_TEST_MESSAGE("Running Findearliestatleast Edge Test");

        std::list<CBlockIndex> blocks;
        for (unsigned int timeMax : {100, 100, 100, 200, 200, 200, 300, 300, 300})
        {
            CBlockIndex *prev = blocks.empty() ? nullptr : &blocks.back();
            blocks.emplace_back();
            blocks.back().nHeight = prev ? prev->nHeight + 1 : 0;
            blocks.back().pprev = prev;
            blocks.back().BuildSkip();
            blocks.back().nTimeMax = timeMax;
        }

        CChain chain;
        chain.SetTip(&blocks.back());

        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(50)->nHeight, 0);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(100)->nHeight, 0);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(150)->nHeight, 3);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(200)->nHeight, 3);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(250)->nHeight, 6);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(300)->nHeight, 6);
        BOOST_CHECK(!chain.FindEarliestAtLeast(350));

        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(0)->nHeight, 0);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-1)->nHeight, 0);

        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::min())->nHeight, 0);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(std::numeric_limits<unsigned int>::min())->nHeight, 0);
        BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-int64_t(std::numeric_limits<unsigned int>::max()) - 1)->nHeight, 0);
        BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::max()));
        BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<unsigned int>::max()));
        BOOST_CHECK(!chain.FindEarliestAtLeast(int64_t(std::numeric_limits<unsigned int>::max()) + 1));
    }

BOOST_AUTO_TEST_SUITE_END()
